Unit 13 - coordination and response Flashcards
(8 cards)
Stimulus
Change in the environment that can be detected by an organism. Can be internal (e.g. change in body temperature) or external (e.g. noise and smell)
Nervous system
An organ system made of the brain, spinal cord & neurons. It detects and respond to stimuli. Main function - coordinate and regulate the body
Neuron
Specialised cell that transmits electrical nerve impulses around your body at high speeds
2 parts of nervous system
- CNS - central nervous system; brain & spinal cord. Responsible for coordinating all reactions & nervous communications around the body
- PNS - peripheral nervous system; nerves in the other parts that are responsible for transmitting the impulses from the CNS to all parts of the body
3 types of neurons
- Sensory - transfers nerve impulses away from the receptor cells when a stimulus is detected to the CNS. Usually long; diagram : neuron in between 2 axons
- Relay - connect one neuron to the next; do not need to be long, found in the CNS/spinal cord; diagram - small with no axon
- Motor - transfer nerve impulses from the brain/spinal cord to the effectors (muscles, glands, etc.). Need to be long. Diagram: neuron with axon only on one side
Relfex action
A means of automatically & rapidly integration and coordinating stimuli with the responses of effectors. Innate (do not need to learn how to do them). Help avoid danger & reduce risk of damage.
Reflex arc
Pathway through the body that brings about a reflex action. Receptor - sensory neuron - relay neuron (in the spinal cord) - motor neuron -effector (produces response to stimuli)
Receptor
Cells that detects different stimuli; make connections with sensory neurons. E.g.
Pain - Nociceptor
Temperature - Thermoreceptor
Pressure- Mechanoreceptors (touch, hearing – waves of sound disrupt pressure)
Sight - Photoreceptors
Smell & taste - Chemoreceptors
